Removing it from peeled shrimp is pretty easy, you just use a knife to cut into the body meat along the length of the body, just deep enough to expose the vein. Then you pull it out.
Here’s how to de-vein shrimp without actually removing the shell:
1. Snip up the back of the shell with cooking shears, just deep enough into the meat to reveal the “vein”.
2. Pull the vein out of the shrimp through the cut in the shell.